Her early career was based on her looks, but it was a different sort of part that really got Charlize Theron noticed. Steve Pratt meets Hollywood's lastest Oscar winner.

CHARLIZE Theron appears the typical, glamorous Hollywood actress as she sashays into the room wearing an off-the-shoulder top, glittering black skirt and high heels. All very different to her look in the role that won her a best actress Oscar this year - as lesbian serial killer Aileen Wuornos.

The South African-born actress can afford to be confident and glowing with a career-making Oscar on her mantlepiece. Yet despite this accolade, and the half-a-dozen other acting prizes she has won for Monster, she admits that nerves made the Academy Award ceremony a bit of a blur.

"I don't know how I got on stage and didn't know what I said until I saw a recording," she says. "I'm not a good speaker in front of people. I'm not a very eloquent speaker.

"But it was incredible. I felt so fortunate with the other awards shows and thought maybe the Oscars would be easier because I'd had a little practice. But the whole experience has been a surprise, so unbelievable and unexpected."

Despite her comments, 28-year-old Theron does talk long and intelligently about her approach to the role. Perhaps she can't feel entirely comfortable because, at the back of her mind, she fears questions about one particular incident in her past: when she was 15, she saw her mother shoot dead her father after he tried to attack her in a drunken rage.

"There are things that people always want to link as the defining stuff of your life and it's not the case. It happened 13 years ago and it's done," she has said. Subject closed, although she's publicly shown her support for her mother, who was never charged, most recently in her emotional thank-you speech at the Oscars.

Theron was a model in her native South Africa before going to the US as a ballerina with the Joffrey Ballet. She was discovered by an agent who witnessed her losing her temper in a queue at a bank.

She went on to be directed by both Woody Allen and Robert Redford as well as starring with some of Hollywood's top names, including Al Pacino, Keanu Reeves, Johnny Depp, Will Smith, Robert De Niro and Ben Affleck.

But she never quite managed to overcome the notion that she was anything more than a pretty face until Monster. In common with many Hollywood actresses, she had to turn ugly to get noticed. Prostitute Aileen Wuornos was a man-hating - and murdering - serial killer who shot seven men and was executed last year in Florida, not long after Theron had signed up to play her in writer-director Patty Jenkins' first feature film.

Jenkins says she saw in Theron someone with the talent, strength and dedication to pull off the part. Seeing a late night TV screening of her film Devil's Advocate while she was writing the script convinced Jenkins that she'd found her leading lady.

Both Theron and her manager read the script and realised this was a great part, if the material was handled correctly. Actress and director met, and immediately clicked. "It was definitely the kind of story I was interested in because I find it very rare that women get to play really conflicted, flawed characters," explains Theron.

"These are parts De Niro or Hoffman get. When they do them, it's accepted and almost cool. When women do them, it's not encouraged because it's uncomfortable to watch. I thought it was a great opportunity because it doesn't happen very often."

SHE was also aware that in the wrong hands - "of a young MTV director, lesbian serial killer, pump up the music kind of film" - it would be a disaster. "So meeting Patty was really important. Immediately after that I wanted to do the film because it was her vision and how she wanted to tell the story.

"I knew that to be part of that would definitely change things for me as an actor. Whether it would win awards, I didn't know. I knew that I would come away challenged and have grown as an actor."

Neither anticipated Monster would strike such a nerve with audiences. Or even that anyone would want to see it. Theron recalls they joked that, if the movie got screened in one art house and eight people saw it on the first night, it would be awesome.

The film has done much better than that, of course, but Theron's doubts persist, just as they did throughout filming. "I drove Patty insane because it was odd for me - I've never had a film-maker come to me and believe in me as much as this woman did," she says.

"Usually I'm the one who has to go in and prove myself. I don't think of myself as this celebrity walking down the red carpet. Patty didn't ask any of that with me. She said, 'I want to make this movie with you. You are the only person who can do it'.

"There were many times I would call her at some crazy hour in the night. I was filled with a lot of anxiety with this film. It's a process of discovery you go through all the time. You don't get to this place where you sit back and relax and say, 'I know what I'm doing'.

"I had many dreams of being replaced. Patty was very understanding and nurturing and supported me through that."

Much has been made of the actress's physical transformation, which renders her virtually unrecognisable. False teeth, contact lenses, extra weight, make-up and lighting are used to turn Charlize into Aileen. Theron thought she'd find the character from the outside, yet the opposite happened when she began researching. There were road trips to places Wuornos lived, as well as reading intimate letters she'd written while on Death Row.

"The more we got to know her emotionally, the more the physical stuff seemed to happen. I realised everything about her physically was there because of the emotional stuff," she says.

"We didn't think she's fat or anything. She had a child at 13, was homeless, didn't know where the next meal was coming from. She said she never took her shirt off. What kind of mindset do you have to be in to think like that? For me, the weight was very much fun to put on and very painful to lose."

AFTER playing Aileen, Theron went on to play another real person - actress Britt Ekland - in a film about the life of Peter Sellers. She has no preference between playing fictional or real people. The story is what matters, she says, and adds that she's never had a vision of the perfect part.

"The difference for me is you have a much bigger responsibility when it's a real life character. Even if they've done terrible things, it's their life and you can't take that away from them," she says. "It was important we walked away from this film and had told the truth, that we had done it with integrity."

That was made possible by her partnership with Jenkins and a small crew shooting the low budget movie in an exhausting 28 days.

"That didn't mean we were taking it easy on each other. Some of the scenes were hard to do. I would be lying on the ground and she would say, 'I'm sorry, we're going to have to do it again'," recalls Theron.

"The only things we wanted to keep in mind were Aileen and the victims, people who were part of the story. We didn't make any decision without having them in mind."

* Monster (18) is now showing in cinemas.